Cylinder Head Gasket Set Bolts Graphite For 1995-1998 Mercury Villager Nissan Quest 3.0L V6 Engine Code VG30E 2 Graphite head gaskets - 26 Head Bolts (8 Long Bolts, 18 Short Bolts) - Viton valve stem seals Intake manifold gasket - Exhaust manifold gasket - Camshaft front - Valve cover gasket - Silicone sealant The head gasket seals in the internal combustion process to make sure maximum compression is achieved and also keeps coolant and oil from mixing together as the two fluids travel from the engine block to the cylinder head. The cylinder head bolts hold the cylinder head and cylinder head gasket in place and ensure that the cylinder head will continue to hold up despite the tremendous amounts of pressure in the combustion chamber. So, if you notice that this part is showing signs of excessive wear, have them replaced immediately. Be sure to have your engine gaskets, and head bolts replace with aftermarket replacement head gasket bolts set as soon as it starts to give you trouble.